| Evidence of Interaction between Polychlorinated Biphenyls and Phthalates in Relation to Human Sperm Motility Russ Hauser,1,2 Paige Williams,3 Larisa Altshul,4 and Antonia M. Calafat5 1Department of Environmental Health, Occupational Health Program, Harvard School of Public Health, Boston, Massachusetts, USA; 2Vincent Memorial Obstetrics and Gynecology Service, Andrology Laboratory and in Vitro Fertilization Unit, Massachusetts General Hospital, Boston, Massachusetts, USA; 3Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts, USA; 4Department of Environmental Health, Environmental Science and Engineering Program, Harvard School of Public Health, Boston, Massachusetts, USA; 5National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA Abstract
Previously, we reported evidence of inverse associations between exposure to some polychlorinated biphenyls (PCBs) and some phthalate monoesters in relation to semen parameters, specifically sperm motility. Because humans are exposed to both phthalates and PCBs and because experimental studies suggest that PCBs may interact with glucuronidative enzymes that are responsible for phthalate metabolism, we explored the potential interaction between phthalates and PCBs in relation to human semen quality. We studied 303 men who were partners in subfertile couples seeking infertility diagnosis from the andrology laboratory at Massachusetts General Hospital. Semen parameters were dichotomized based on World Health Organization reference values, and phthalate and PCB levels were dichotomized at their respective medians. After adjusting for age and abstinence time, for below reference sperm motility there was a greater than additive interaction between monobenzyl phthalate and PCB-153 [relative excess risk due to interaction (RERI) = 1.40 ; 95% confidence interval (CI) , 0.41-3.22], sum of PCBs (RERI = 1.24 ; 95% CI, 0.15-2.94) , and cytochrome P450 (CYP450) -inducing PCBs (RERI = 1.30 ; 95% CI, 0.21-3.06) . For below-reference sperm motility, there was also a greater than additive interaction between monobutyl phthalate (MBP) and PCB-153 (RERI = 1.42 ; 95% CI, 0.09-3.76) and CYP450-inducing PCBs (RERI = 1.87 ; 95% CI, 0.56-4.52) and a suggestive interaction between MBP and sum of PCBs (RERI = 1.35 ; 95% CI, -0.11 to 3.48) . In conclusion, because there are important risk assessment and public health implications of interactions between these two ubiquitous classes of compounds, further studies need to be conducted to confirm these results and identify potential mechanisms of interactions. Key words: environmental, epidemiology, human, sperm, synergy. Environ Health Perspect 113:425-430 (2005) . doi:10.1289/ehp.7305 available via http://dx.doi.org/ [Online 10 January 2005]
Address correspondence to R. Hauser, Occupational Health Program, Department of Environmental Health, Harvard School of Public Health, Building 1, Room 1405, 665 Huntington Ave., Boston, MA 02115 USA. Telephone: (617) 432-3326. Fax: (617) 432-0219. E-mail: rhauser@hohp.harvard.edu We thank the staff of the Vincent Memorial Obstetrics and Gynecology Service Andrology Laboratory and In Vitro Fertilization Unit at Massachusetts General Hospital ; our research nurse, L. Godfrey-Bailey ; computer programmers L. Pothier and J. Frelich ; and research assistants A. Trisini and R. Dadd. We thank R. Stolyar and S. Forsberg for the chemical analyses of the polychlorinated biphenyls and M. Silva, J. Reidy, A. Herbert, E. Samandar, and J. Preau at the CDC for the analyses of the phthalates. This study was supported by grants ES09718 and ES00002 from the National Institute of Environmental Health Sciences, National Institutes of Health. The authors declare they have no competing financial interests. Received 1 June 2004 ; accepted 10 January 2005.
The full version of this article is available for free in HTML or PDF formats. |
